High-frequency signaling system



Sept. 4, 1928'. 1,683,230

I w. R. G. BAKER HIGH FREQUENCY SIGNALING SYSTEM Filed May 5, 1926 Inventor: Walter Rfibaker,

Hus Attorney.

Patented Sept. 4, 1928.

UNITED STATESv PATENT err-ice.

WALTER R. G- BAKER, OF SCHENECTADY, NEW YOBK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

HIGH-FREQUEN CY SIGNALING SYSTEM.

Application filed ma 5, 1926. Serial No. 106,966.

My present invention relates to systems for the transmission of high frequency signals, and more particularly to systems in which high frequency power is supplied by means of electron discharge devices;

It is customary in supplying an appreciable amount of high frequency power bymeans of electron discharge devices, to employ as the original high frequency source an electron discharge device of comparative mitting circuit in some cases involves certain difficulties. If it is desired to vary the amount of power supplied it must be done either by cutting some of the devices out of the circuit orby varying the voltage or other operating conditions of the amplifying devices. If a change in power is accomplished by changing the number of devices employed, other changes must be made in the circuit connections to maintain the desired tuning of the circuits and the efficient sugply of power to the transmitting circuit. If, on the other hand, the change is made by varying the operating conditions of the devices the efficiency of operation will be materially lower at any power output differing from the optimum.

Still another disadvantage which is especially troublesome at higher frequencies lies in the fact that with several devices connected in parallel the interelectrode capacities are also in parallel and the tendency of the amplifying system to itself generate high frequency oscillations is greatly accentuated.

The object of my invention is to overcome these disadvantages, and to provide a system which will be readily adaptable for use with any frequency desired, or in which the power delivered may be readily changed without changing the tuning of any of the circuits, and one in which substantially the best operating efiiciency may be obtained irrespective of the amount of power supplied.

In attaining the. object of my invention, I

provide a plurality of independent ampli-- iier units each of which is adapted to supply power to the transmitting circuit independently of the other units. Each amplifier unit in accordance with my invention is provided with a tuned output circuit, and if one or more units areremoved from the system no change in the tuning becomes neccssa-ry. The system also may be so proportioned that any desired amount of power may be supplied to the transmitting circuit atgood efficiency merely by changing the number of amplifier units which are in oper-' ation. Also, in case a'tube in one unit fails the other units may continue to carry the load while that tube is being replaced. The arrangement described has the further advantage that the number of devices which are'connected in parallel to a tuned output circuit is greatly reduced, and therefore'the diagrammatic-ally one circuit organization whereby my invention may he carried into effect. I

I have indicated in the drawing a. power supply system for supplying signaling currents to a transmitting circuit which is indicated as an antenna. 1. The primary source of oscillations in the system shown is an electrondischarge device 2 which is arranged to produce high frequency oscillations in its output circuit. I have indicated in the drawing only two amplifier units, one comprising amplifier devices 3 and 4 and the other employing amplifier devices 5 and 6. The amplifying devices 3 to 6 have their input circuits excited from the coils 7 and 8, which are coupled to the tuned output circuit 9 of the oscillator 2. The two amplifying devices of each unit are connected in push-pull relation and the output circuits are tuned to the desired frequency by means of the condensers 11 and 12 and variable inductance 13, 14, 15 and 16. Coupling coils 17 and 18, which are connected in seriesrelation in the transmitting circuit receive energy supplied from the output circuits of the two amplifying units. It will of course be understood that as many amplifier units as desiredmay thus be connected to a transmitting circuit with the secondaries of the cou pling transformers coupled. in series or parallel as desired. Power for the operation of the systemis supplied from two direct current mains in ,dicated at 19, 20. The positive-main 19 is connected directly to the plates or anodes of various devices. Tunedtrap circuits .21 and 21 are provided between the, main 19 and each amplifierunit to prevent a reaction between the different amplifying units.

Biasing potentials for the various amplifier lgrlds'are obtained bymeans of. thermionic rectifiers- 22 which are supplied with alternating current from any suitable source by means I of transformers Similarly biasing potential for theqgrid of the oscillator 2 is provided by means of a thermionic rectifier 24 supplied with alternating current by a transformer 25. a The biasing potential for the grid of oscillator 2 may be normally of such a value that no oscillations would be produced.

.l/Vhen it is desiredto transmit "telegraphic signals therelay 26 closes a shunt circuit around the grid condenser 2mm resistance 28, and thereb permits the production of, oscillations, ant the supplying of the desired current to the transmitting circuit.

. While I have shownand described only one embodimentof'my invention, it will be apparent that many modifications may be made in the circuit connections. asfwell as in the particular manner of V )erating the various devices employed without departing by Letters Patent of the United States, is

from the scope of my invention in the appended claims. Vhat I claim as new and desire. to secure asset forth 1. The combination in a-high frequency signaling system of a source of high frecircuit. y i 2. The combinatin in a high frequency.

quency current of substantiallya single frequency, a plurality, of amplifying units Which-are excited from said source, the output. circuit of each-of said amplifyin units being" tuned to the" frequency of; sai high frequency currents transmitting circuit and an independent coupling between each of said output circuits and said transmitting signaling system ofL-a source of hi h fr equency current,ja plurality "of/amp ifying" units; which areexcited from said source, allofsaid amplifyinglunits being tuned to amplify currents of a common frequency, or frequencies, andeach of said amplifying units comprising apair-of electron discharge devices having: their output circuitsconnected i in pushpull relation, andan independent coupling fromthe output circuitof each am plifyingunit to a. transmitting circuit;

3. Thecombination in a high frequency signaling system of a source of high fre-' quency current, "a plurality of amplifying units which are excited from said source,

each'of said amplifying units comprising a pair of electron discharge devices connected inpushull relationand having an inde pendentlytuned output circuit and an in;

dependent coupling between each of; said tuned output circuits and a transmitting circuit... V V a 1 4. The combination. in thigh frequency system of a source of radio frequency current, a plurality of amplifying. units which a are excited from: said. source, a; tuned output 1 circuit for each of; said. amplifying units,. all of said output circuits being tuned to-Fa- 

